It is well known that hardness in water sources varies widely in composition depending on the source and results in scale deposition and sedimentation wherever water is used. Scale deposition and sedimentation is particularly troublesome in residential and commercial hot water heaters. In these systems, the formation of hard water scale and sediment rapidly reduces the efficiency of heat transfer thus increasing the cost of heating the water either by gas or electricity. Also, scale and sedimentation will increase the possibility of corrosion in the water heater which will eventually result in leakage and the necessity of replacement.
There have been some physical means that have been developed to minimize the formation of scale and sediment in hot water heaters. The creation of a vortex by the water inlet stream has been used to generate a turbulence inside the tank during water addition which supposedly keeps the solids that are formed in suspension so that they can be removed in the water flow. This would only function during water flow and does not prevent sedimentation or scale formation on the heat exchange surface when water is not flowing. Other devices, such as magnets, have been employed to prevent hard scale deposits but are of questionable effectiveness and usually require frequent tank drainage.
Further improvements are needed for cleaning and/or maintaining hot water heaters free from scale and sediment.